Short answer: if you already have ductwork and you are cooling a whole house, central air is almost always the right call in South Florida. If you are cooling an addition, a converted garage, a Florida room, or one bedroom that runs hot, a mini split is cheaper, faster to install, and does not require tearing into walls.
Most comparison articles will not commit to an answer. We just did. Now here is the reasoning, because the exceptions matter more than the rule.
One thing to understand before anything else: your AC in Miami runs 8 to 10 months a year. Up north it runs 3 or 4. Every difference between these two systems gets multiplied by that number. A system that is 10% less efficient is not 10% worse here. It is 10% worse, three times as often.
The Comparison, In One Table
| Central Air | Mini Split | |
|---|---|---|
| Typical installed cost | $4,000–$12,000 | $2,500–$6,000 per zone |
| Needs ductwork | Yes | No |
| Install time | 1–2 days | Half a day to 1 day |
| Cools a whole house | Yes | Only with multiple zones |
| Per-room temperature control | No, one thermostat | Yes, every zone independent |
| Indoor unit | Hidden | Visible on the wall |
| Efficiency at equal SEER | Loses 20–30% to duct leakage | No duct loss |
| Best for | Existing homes with ducts | Additions, garages, single rooms |
| Florida minimum SEER | 15 | 15 |
Both must meet Florida's 15 SEER minimum on new installs. Both need a permit in Miami-Dade, Broward, and Palm Beach. Anyone who tells you otherwise is telling you something useful about themselves.
Central Air: The Default, And Usually Correct
Central air uses one outdoor condenser, one indoor air handler, and ductwork running through your attic or ceilings. One thermostat controls everything.
For a typical South Florida house that already has ducts, this is the answer. Installation runs $4,000 to $12,000 depending on tonnage. You are replacing equipment, not rebuilding infrastructure.
The catch nobody mentions in the showroom: your ducts are in the attic. In August, that attic hits 130 degrees. Cold air travels through it on the way to your bedroom. Duct leakage in a typical Florida home costs 20% to 30% of your cooling. A 16 SEER system with leaky attic ducts can underperform a 15 SEER system with tight ones.
So when someone quotes you a central air replacement and does not mention duct sealing, they are quoting you half a job. (We would say that is unusual. It is not unusual.)
Central air also has a single-zone problem. One thermostat, usually in the hallway, decides the temperature for the whole house. Your west-facing bedroom takes afternoon sun for four hours and the hallway does not. The hallway wins the argument every time.
Mini Splits: Right For Specific Problems
A mini split is an outdoor condenser connected to one or more indoor units by refrigerant lines running through a three-inch hole in the wall. No ducts. Each indoor unit is its own zone with its own remote.
Cost runs $2,500 to $6,000 per zone installed. That number is why the math flips depending on how many rooms you are cooling.
Where mini splits genuinely win in South Florida:
Additions and converted garages. Extending ductwork into a new space often costs more than a mini split and performs worse. If you added a room, this is your answer.
The one room that never gets cool. Rather than replacing a working central system to fix one bedroom, add a mini split to that bedroom. It is a targeted fix at a fraction of the cost.
Florida rooms and enclosed patios. These spaces have more glass and more heat gain than the rest of the house. They need their own zone, and the central system was never sized for them.
Homes with no ductwork. Older Miami homes, some historic properties, and homes that ran on window units. Adding ducts to a house that never had them is a demolition project.
Where they lose: cooling a full four-bedroom house with mini splits means four to six zones. At $2,500 to $6,000 each, you are past central air pricing and you have five indoor units mounted on your walls. Some people are fine with that. Most people, when they see the first one installed, are less fine with it than they expected.
The Efficiency Argument, Honestly
Mini splits are more efficient than central air at the same SEER rating. That part is true and it is not close, because there are no ducts to leak into a 130 degree attic.
But the comparison people actually face is not "same SEER." It is "new mini split versus new central air," and a modern central system with properly sealed ducts closes most of that gap. A high-efficiency unit saves $50 to $150 a month on a South Florida electric bill either way.
Here is the part that matters more than the brochure: the install quality affects your bill more than the equipment choice does. An oversized system short-cycles, never runs long enough to pull humidity out of the air, and leaves your house at 74 degrees and clammy. That is not a comfort problem you can fix with a thermostat. That is a sizing problem, and it happened on install day.
Which brings us to the thing we care about most.
Sizing Is Where Florida Installs Go Wrong
The most common mistake in South Florida AC is a system that is too big. It sounds backwards. It is not.
Air conditioning does two jobs here: lower the temperature and pull out humidity. Removing humidity takes runtime. An oversized unit hits the target temperature fast, shuts off, and never runs long enough to dehumidify. You get a cold, damp house, a compressor that cycles itself to death, and a shorter equipment life.
A properly sized system runs longer at lower capacity. It costs less to operate and it lasts longer. AC lifespan in South Florida is 10 to 15 years because of how hard these systems work. Oversizing takes years off that.
Proper sizing comes from a Manual J load calculation: square footage, insulation, window area and orientation, ceiling height, air sealing. Not a guess based on square footage alone, and definitely not "whatever was here before," because whatever was here before may have been wrong for 12 years.
When We Would Tell You Not To Hire Us
If your central system is under eight years old and one room runs hot, do not let anyone sell you a replacement system. Get the ducts inspected first. A blocked or disconnected duct run in the attic is a common problem, and it is a repair, not a replacement.
If your AC is 12 years old and still working, and someone tells you it is an emergency in July, ask them why it became an emergency during the busiest month of the year. Get a second opinion. Replace it in a shoulder month when you can actually shop the price.
And if you are quoted a new system without anyone measuring a window or opening the attic, that quote is a guess. Guesses are free. This one will not be.
Cost Summary
| Scenario | Typical Range |
|---|---|
| Central AC replacement, existing ducts | $4,000–$12,000 |
| Central AC plus duct sealing | Add $1,000–$3,000 |
| Single mini split zone | $2,500–$6,000 |
| Three-zone mini split system | $7,000–$15,000 |
| Whole home mini split, 4+ zones | Often exceeds central air |
Financing is available with $0 down and terms up to 15 years. PACE financing is common in Florida for high-efficiency equipment and is worth asking about before you sign anything.
Frequently Asked Questions
Are mini splits cheaper than central air?
Per zone, yes. For a whole house, usually no. One mini split costs less than a full central system. Five mini splits usually cost more.
Do mini splits work in Florida humidity?
Yes. They dehumidify well when properly sized, and having per-room control helps with the rooms that run hot and damp. The sizing rule applies to both system types equally.
Do I need a permit to replace my AC in Miami-Dade?
Yes. AC replacement requires a permit in Miami-Dade, Broward, and Palm Beach. An unpermitted install will not appear in your permit record, which becomes a problem at resale and can complicate an insurance claim.
What SEER rating should I get in South Florida?
Florida requires 15 SEER minimum on new installs. Because your system runs 8 to 10 months a year here, a higher rating pays back faster than it would in a milder climate. Somewhere in the 16 to 18 range is the sweet spot for most homes before the price curve gets ahead of the savings.
How long does an AC last in South Florida?
10 to 15 years. That is shorter than the national average, and the reason is runtime. Correct sizing and annual maintenance are the two things that push you toward the top of that range instead of the bottom.
The Decision, Simplified
Have ducts and cooling a whole house? Central air. Cooling an addition, a garage, or one stubborn bedroom? Mini split. No ducts at all and no interest in adding them? Mini splits, zone by zone.
Whichever you choose, spend the money on correct sizing and a proper install before you spend it on a higher SEER number. The best equipment installed badly loses to decent equipment installed right, every summer, for the next 12 years.
Call (786) 983-7928 for a free estimate. We will do the load calculation, tell you which system your house actually needs, and if the answer is "repair what you have," we will tell you that too. It makes for a worse sales pitch and a better August.